Laser Cut Balsa, Love or Hate?

Well, I grew up in the days of cut-your-own-balsa, and most of the rockets I built back then came out OK, but I have no terrific attachment to the romance of hacking out the fins myself (although I still do sometimes on scratch-builts and kits without LCB).

Plus the pre-cut fins are more uniform and save some time which is probably put to better use sanding and finishing.

It's not a deal-breaker to me either way.

The main difference is that back in my junior-high days 40 years ago, the X-Acto knife I usually used was a very thin-handled lightweight knife, which didn't really allow a firm hand to be used in cutting (the knife itself would flex). As a result I tended to use a very light touch which sometimes resulted in wiggly fin edges.

After my decades-or-more sabbatical from rocketry I learned to use heavier utility knives or thick-handled knives with a little more heft, which allows for medium-weight balsa to be cut more firmly and result in more consistent edges.

Either way works.

JStarStar said:

The main difference is that back in my junior-high days 40 years ago, the X-Acto knife I usually used was a very thin-handled lightweight knife, which didn't really allow a firm hand to be used in cutting (the knife itself would flex). As a result I tended to use a very light touch which sometimes resulted in wiggly fin edges.

After my decades-or-more sabbatical from rocketry I learned to use heavier utility knives or thick-handled knives with a little more heft, which allows for medium-weight balsa to be cut more firmly and result in more consistent edges.

Click to expand...

X-Acto knives were recommended and about all we really had to work with in those days along with single edge razor blades....yuckers on both of those tools. After many years of graphics applications, I discovered how well I liked a good quality breakaway knife and a ruler with a metal edge. I can make the best balsa cuts with these and they support the note, "having the proper tools" to execute the job at hand. If I still had to use X-Acto's, I'd be all over the LCB's as well. Kudos to owning a Dremel also! Here's my knife of chioce. The saw on the bottom is also a nice cutting tool.

I'd have to say love. when I cut my own fins I tend to chip corners easily.

jflis said:

For other kits, the body tube cutting is for a special look (like angled cuts and such). Learning THAT particular skill really opens up the possible design ideas

Click to expand...

Yes, indeed. That's exactly what I was referring to.

Sorry about my lengthy digression on the CRF-2.5-4. I just thought it was the coolest thing when I saw that.

Creativity comes from the soul. An art form from the heart. As a designer I can respect this because to me modeling is an art form. Not just a "build and shoot". I may not have the best finishes on my rockets but my heart went into designing them building them. I do it with craftsmanship. Michelangelo mixed his own colors when he painted the Sistine Chapel. Remember what he did. Nuff said.

Gary Byrum said:

Creativity comes from the soul. An art form from the heart. As a designer I can respect this because to me modeling is an art form. Not just a "build and shoot". I may not have the best finishes on my rockets but my heart went into designing them building them. I do it with craftsmanship. Michelangelo mixed his own colors when he painted the Sistine Chapel. Remember what he did. Nuff said.

Click to expand...

Good point. Creativity is also a matter of inspiration, the spark of a new idea or the urgency that comes from seeing a problem in a whole new way.

All fine art painters mix their own colors. That's what the (physical) palette is for. It's one of the things I learned in art school way back in the previous millennium.

I also think that anything you do, design, quality, strength, attention to detail, finish; shows whom you are. To me, I put every effort into making whatever I do to be the best it can be, and don't settle for "good enuf".
I don't care how long it takes, but that's just me.
And I agree, it's all an art form in one way or another.

I'm with the folks that have no great preference on laser vs hand-cut wood. It takes longer by hand but I feel like I can get pretty much equivalent results. The Olfa type cutting mat, a good steel rule, and stack-sanding identical pieces are the critical parts. For knives you can use whatever floats yer boat. I'm kinda old school and use a medium X-acto handle a lot, usually with a blade with the last 1mm or so snapped off, which makes the cut less "swervy". For anything over 3/32" stock I try to use a razor saw for the straight cuts.

It might be the end of an era though - in 10 years or so I bet a lot of model builders are going to have their own mini laser cutters.

caveduck said:

- in 10 years or so I bet a lot of model builders are going to have their own mini laser cutters.

Click to expand...

Whoa! That's a thought which hadn't happened here yet.

Woody's Workshop said:

I also think that anything you do, design, quality, strength, attention to detail, finish; shows whom you are.

Click to expand...

Well, let me say this about that and quote something I posted in a Farcebook group a little bit earlier this am,

Forrest Scott Wood said:

A bit of Wednesday morning math.
(chronic fatigue) + (fibromyalgia) + (neuropathy) + (back issues) + (shaking spray paint cans for 3-4 days in a row) + (fronts and rain today) = was it worth it to get model rocket kit parts and a garden scale train car painted?
Answer - not just yes, but oh, hell yes!
It's part what makes me, me; and part how I keep my sanity

Click to expand...

I use standard #11 and #2 X-Acto blades for everything up through 3/16" basswood. I cut each fin, with its curved transition from leading edge to tip edge, for my Javelin XL out of 3/16" birch plywood with a utility knife, then clamped them together and gang-sanded them with my sanding block to even them up. I use razor saws to cut strip stock and dowels, but they aren't precise enough to be used to cut things like fins. The only power tools I own are a Dremel, a power drill and a palm sander. I'd like to own more, but finding room in the budget has been a challenge. The Dremel is the most expensive tool that I have ever owned. I dream of someday having a drill press.

another bit about lcb, if you're carefull when you remove the fins, you can use the 'waste' as a template for the paper skins.

Good note Rex! I used paper skins on my Mars Lander the same way.

I cut my fins the redneck way, I use a print out template and cut out the fins with my pocket knife. Works for me. LOL.

HomeBuiltRocketeer said:

I cut my fins the redneck way, I use a print out template and cut out the fins with my pocket knife. Works for me. LOL.

Click to expand...

And then there's the backwoods way, which is to use rectangular slabs for the fins on every rocket you build.

I recently laminated light card stock to three sets of laser cut balsa fins. A little white glue and some time under the pressure of some 10 lb. barbells and they came out very nice. A test piece was made and then bent to check durability. I could bend the piece until it the two ends touched and it would not break. i could bend it back and forth until the balsa fibers had all seperated into mush and could still straighten out the piece into its original shape but the surface of the cardstock wasn't smooth any more.
The white sealed side of the card stock takes paint without any prep work and looks great.
The fins are for a Quad Runner and a modified Big Bertha. The Big Bertha fins were trimmed and the remainder was too nice to throw away so they became forward mounted fins. The Quad Runner fins are of two piece construction and the laminating has added much needed strength and durability. *(I can not beleive that Quest has not changed this kit to "through the wall" fin design).
I am so pleased with the finish and the ease of production that Iam planning on laminating some thin basswood and testing it. If all goes well I will help my son build a BT-50 kit with this type of fin. He has no patience for sanding.

I gotta say I'm not the biggest fan of laser cut balsa fins.... at least the ones kits provide. Most of the time I cut them out, trace them onto a piece of paper, scan that paper and then print my own templates. This allows me to use my own balsa or whatever I choose to make my fins out of and then I can hand cut them. That is my at home technique.

We have an epilog laser engraver in the model shop at school (model making student) so I generally measure the fins, draw them in CAD and laser them out myself out of whatever material I want.

My teacher is not a fan of me using the $30,000 laser for rocket fins lol

Canadianghandi said:

I gotta say I'm not the biggest fan of laser cut balsa fins.... at least the ones kits provide. Most of the time I cut them out, trace them onto a piece of paper, scan that paper and then print my own templates. This allows me to use my own balsa or whatever I choose to make my fins out of and then I can hand cut them. That is my at home technique.

We have an epilog laser engraver in the model shop at school (model making student) so I generally measure the fins, draw them in CAD and laser them out myself out of whatever material I want.

My teacher is not a fan of me using the $30,000 laser for rocket fins lol

Click to expand...

I'm trying to parse this out. You aren't a fan of laser-cut fins, so you laser-cut your own instead. So... the problem isn't the laser-cutting process, but rather that someone else did it? Or the fact that the fins are included with the kit at no extra charge, and you would prefer to pay an addition amount for them? Or that you prefer to cut your own fins, and just happen to have a school-provided laser-cutter available that you can steal some time on for free when your teacher isn't looking? Laser-cut fins aren't any good; you prefer to use laser-cut fins instead.

MarkII said:

I'm trying to parse this out. You aren't a fan of laser-cut fins, so you laser-cut your own instead. So... the problem isn't the laser-cutting process, but rather that someone else did it? Or the fact that the fins are included with the kit at no extra charge, and you would prefer to pay an addition amount for them? Or that you prefer to cut your own fins, and just happen to have a school-provided laser-cutter available that you can steal some time on for free when your teacher isn't looking? Laser-cut fins aren't any good; you prefer to use laser-cut fins instead.

Click to expand...

The material that most companies give you is far from perfect. I prefer my fins to actually be flat and not full of divets. Whenever I try to sand the fins they always pop out. For me it is much easier to get a sheet of whatever material be it plastics, balsa, bass, whatever it may be and do all the prep work for one sheet. It is much easier to take a sanding block and make a sheet all the same thickness and have a smooth surface. Then cutting the fins out by hand or laser leaves a small amount of work to be done. You may be a fan of extra un-needed work and wasting money but I am not.

OK, that is the point I was attempting to make.
I prefer to prep the whole sheet, then cut out the fins.
To me, it's easier that way than to try and do each individual piece seperately. That's why I don't care for laser, die or otherwise pre cut fins.
Since I have a wood shop, I have a multitude of machine available (not including a laser machine) to cut out after the stock is preped.
Since I use TiteBond II to do almost everything, the bigger the stock, the easier it is to work with.
But that's just me. I'd rather have a rack of pre-filled, sanded and ready for primer balsa stock on the shelf in 6" x 48" than start from scratch on little pieces. RA and bad eyes is not getting better so anything I can do personally to make things easier, I go for.
A toast to old timers!

Woody's Workshop said:

OK, that is the point I was attempting to make.
I prefer to prep the whole sheet, then cut out the fins.
To me, it's easier that way than to try and do each individual piece seperately. That's why I don't care for laser, die or otherwise pre cut fins.
Since I have a wood shop, I have a multitude of machine available (not including a laser machine) to cut out after the stock is preped.
Since I use TiteBond II to do almost everything, the bigger the stock, the easier it is to work with.
But that's just me. I'd rather have a rack of pre-filled, sanded and ready for primer balsa stock on the shelf in 6" x 48" than start from scratch on little pieces. RA and bad eyes is not getting better so anything I can do personally to make things easier, I go for.
A toast to old timers!

Click to expand...

Do you stick with balsa and basswood or do you use other kinds? I figured since you are a cabinet maker you may have tried various other kinds of wood. I'm always looking for different materials to make things out of.

So it's not the laser-cutting that is the issue, but rather the type or quality of the fin stock that was used? That's an entirely different issue. It is the fin material, not the manner in which the fins are cut, that you take issue with. This thread could have been about 45 posts shorter, then...

No, Quality of the matterial isn't an issue. God knows I've used crap that should have been burned. It's just easier to deal with in sheet stock than little pieces the way I do things.
I use the wood putty for woodwork when needed, but I would NEVER put it on my fins. There is no value to me in that. I use glue for a filler because I understand the strength it adds for the weight. And it's far easier to sand as a whole sheet than little pieces.
Perhaps I should have worded the opening post differently so it was better understood what I was trying say. Reading everyone's posts, it went in several directions. But it did bring out some interesting things, and I did learn a few things. And I hope some others did as well.
Like who has kits with die cut fins. How laser cut adds cost. Different finishing techniques. It's all good and I am more than pleased for what has been posted, as I hope others have been too.

I have used other materials for fins and cones. 99% has been balsa. I have a sheet of laminated plastic of some sorts from a store display I'm thinking I want to try. Not sure what it is exactly, very flexible. It's been stored for years in a roll. It's olding that shape. It's been laying on the shop floor for about 2 weeks and shows little sign of wanting to go flat. But storage has been in a shed where it gets 120 degrees or more in the summer, then down to 30 below in the winter. So it may take a very hot day and some sun to make it lay flat. Not sure the UV rays will do to it, but will see.
I've only done the Estes thing for years, so anything else is new. But I did purchase a ISQY Tomahawk by AeroTech recently and am so patiently awaithing to start that build. I have to get some kevlar and a engine retaining system, so until the money is there I gaze upon it with anticipation.

Which brings me to my next thing, since I can't move forward without a plastic transistion I need. My BT-80 upscale of the Estes Wizard. I will probably take photos and start a build thread so everyone understands how I work...beside slow as an old Fart that I am.

It has indeed been an interesting discussion, which is why I have been following it for the past 3 weeks.

Regardless of whether the fins are already cut or I cut them myself, I prefer to finish them individually. One of the reasons is that it is the only practical way to do it in my tiny workspace. I don't have woodworking tools, or any power tools to speak of; the most technical tool that I use on a routine basis is a sanding block. I have been building rockets of all kinds (low-, mid-, high-power and micros) this way since I resumed the hobby seven years ago. Aside from not having the budget to invest in equipment, I just like the feel of working the material by hand. On several occasions I have tried to prep stock first before cutting out the parts, but I never cared for the results I got.

No disrespect, but I have to be honest: coating balsa fin stock with Titebond II to finish it before cutting out the fins sounds like a rather strange process. But hey, you're the professional here, not me, so what do I know? How do you control the warping? No matter how long I give it to dry, wood glue always ends up getting gummy on me when I sand it. I suppose I could wait until winter and sand it outdoors in sub-zero weather, though.

I buy nearly all of my balsa stock from my local Michael's, and I inspect every sheet in the bin before selecting the few that I eventually purchase. I have rarely had damaged or poor quality balsa in the kits that I have built, but when I did I simply recreated the part in question with my own material and moved on. No big deal. I guess I haven't built enough kits in 11 total years in the hobby to get worked up over this issue.

I don't mind laser-cut balsa. Speeds up the building process. I ether coat the fins with CA or cover with origami paper.

RocketT.Coyote said:

I don't mind laser-cut balsa. Speeds up the building process. I ether coat the fins with CA or cover with origami paper.

Click to expand...

Yeah,

I don't mind Laser Cut when it comes with a Kit, but it complicates things, as I then have to make a Template anyway in case I screw up a Fin and need to make a repacement or repair.
I prefer working with a Template and cutting them out so I can just make a spare as I make the ones needed.
Then I also know that I will have used the same wood for them, and that a spare will be identical to the rest.

When you pop a fin out of laser-cut stock, you have a ready made template. No work involved.

foamy said:

When you pop a fin out of laser-cut stock, you have a ready made template. No work involved.

Click to expand...

Sure, but I scrap the excess balsa. I just scan the fins on the scanner or draw one and scan it to the computer.
I also just figured out how to print the fin templates on Openrocket.

When we first started back up, I remember the discussion about laser cut fins. We watched the thread because many did not like the pre-cut fins. Carl decided to keep cutting the fins and for the "die-hard do-it-yourselfers", a template was provided if you wanted to cut your own. As years passed and some of the fins became more complicated, most were pleased we provided this service.

Count me in with the folks that like them. I sorely wish I had easy access to a laser cutter.